Approximately 10% of all the plastic that we produce ends up in the oceans, where it can cause irreparable damage to the ecosystem. Some of the tiny nanoplastics (plastics that are on the scale of a nanometre, i.e. 1 billionth of a metre) enter the food chain when they are consumed by animal plankton. This study has demonstrated that upon eating the infected plankton, the plastics pass into the bloodstream of fish and are so small that they can permeate the blood-brain barrier and thus accumulate in the fishes’ brains.

The researchers in this study also demonstrated that fish which were found to have nanoplastics in their brains displayed strange behaviours, such as eating slower and being more reluctant to explore their surroundings. The researchers believe that these behavioural changes may be the result of brain damage brought about by nanoplastics in the brain. Further study is required to see if the nanoplastics accumulate in fish organs other than the brain, as if they do this will likely have severe implications for fish-eating humans and other animals.